Manual

Using the Digital Outputs and Inputs 8-1
8 Using the Digital Outputs and Inputs
The Digital Outputs
The Digital Outputs are optically-isolated logic outputs tied to a back-panel connector. They
are always High True (i.e. High = True, Low = False), assuming you connect them in the
grounded-emitter configuration. At power up and Emergency Stop they are all set False (i.e.
Low).
For the connector pinout and electrical specifications, see the Automove Operation manual.
The Digital Outputs can be used to control any sort of external hardware such as relays,
solenoids, valves, lamps, measurement devices, cameras, etc.
There are several advantages to using the Digital Outputs instead of, say, some other output
channel connected directly to your host computer. First, the Digital Outputs can be tightly
synchronized to the move sequence. Second, they can be actuated by a Download Sequence,
so that your system can operate without a host computer. Third, the value output can be
changed via the Digital Inputs, so that manual or externally-controlled interaction is
possible.
The Digital Outputs are affected by the following ACL commands: CD ("Change Digital
Outputs"), MD ("Mid-move Digital Outputs Changes"), MM ("Multiple Mid-move Digital
Outputs Changes"), OD ("Output Digital Outputs State"), PD ("Pre-move Digital Outputs
Changes"), TD ("Toggle Digital Outputs"), and WD ("Wait After Digital Outputs
Changes"). They can also be affected by the Digital Inputs if personality parameters 36-38
are set appropriately; see Digital Inputs, below.
Simple Use
The easiest way to use the Digital Outputs is to send the CD command as part of your move
sequence. As soon as the CD command is executed, the Digital Outputs change to the
specified new values.
The <which> parameter of the CD command can simplify your host software. If your host
program has several separate subroutines to control several different devices, each
subroutine can change only the Digital Output(s) it is concerned with, leaving the others
alone.
If your external hardware needs time to respond before the next operation can begin, you can
use either the WA ("Wait") command or the WD command. If you find yourself sending the
same WA command after each CD command, you can switch to using a single WD
command before all the CD's.